Six months ago I highlighted a wonderful piece of work by Greater Greater Washington that took a look at ridership on the DC Metro. Well I finally got off my butt and did a similar thing for BART. I asked someone at BART who was affiliated with the recent rider survey for data on trips by station entry and exit.
Ask and ye shall receive; BART sent me an excel file containing average weekday origin/departure numbers for the spring and summer of 2009. I crunched the numbers a little and came up with the following
This map shows the number of people on each segment of track (between each station) on the BART system on an average weekday last spring/summer. You can also download a PDF showing the absolute numbers I came up with.
The map itself is probably not terribly surprising to anyone who is familiar with BART; the vast majority of its riders are on the tracks between downtown San Francisco and downtown Oakland.
I will be crunching more number in the future and making new illustrations of what I find.
One thing that immediately jumps out at you when looking at the raw data is the number of people who enter and exit out of the same station. You'd expect this number to be very small, and it is for most stations:
El Cerrito Plaza: 8
Castro Valley: 6
South San Francisco: 5
But for a few stations the number is high. Like really high:
North Concord/Martinez: 3175
San Bruno: 3246
This striking ridership is all at stations far from the downtown core where most trips start or end. My guess is that these riders are taking advantage of the excursion fare because it's cheaper than the far to their destination. These riders may have a Fast Pass or some other means of entering and exiting the station at the other end of their trip, and so are committing some kind of high-class fare evasion to avoid paying the increasingly expensive cost of their commutes.
Curiouser and curiouser.
I received an email from the BART staff person who sent me the data for the above diagram:
The data sent to you previously was an average of various days from each of these months. There appears to be some sort of bug when selecting specific dates to come up with an average ... We are working on the bug and hope to have it resolved soon.I'll be updating the above diagram again, and working on a few new ones in the near future.